The Cell Morphology Core (CMC) laboratory has been constructed to meet the increasing demands of cell biology and transgene detection in the area of gene therapy research. John Tazelaar, M.D., a board eligible certified pathologist, serves as Assistant Director in charge of the CMC. Routine morphology support in the form of paraffin, frozen, and glycolmethacrylate sectioning for light microscopy as well as standard transmission electron microscopy (TEM) are provided as comprehensive services to P30 investigators. In addition, the core emphasizes state-of-the-art methodologies for detecting transgene expression including in situ hybridization, immunohistochemistry, and histochemical detection of beta- galactosidase and alkaline phosphatase reporter genes. P30 investigators participate in CMC services in several ways. Most activity is in support of basic research provided in an ad hoc way to the many investigators who work in the area of gene therapy for Cystic Fibrosis and Genetic Diseases. The CMC also provides full service support to the Translational Research Program in toxicology studies and the clinical trials in the analysis of cells and tissues for evidence of pathology and transgene expression.